1. Adrenergic Blockers
Asmah Nasser, M.D.

3. Direct Adrenergic Antagonists
Alpha blockers
Beta blockers
Alpha plus beta blockers

4. Alpha Blockers (non-selective)
Phenoxybenzamine (Non-competitive)
Phentolamine (competitive)
Ergot alkaloids:
Ergotamine
Ergotoxine

5. Phenoxybenzamine Non-competitive alpha adrenergic antagonist.
Net effect: α 1 blockage > α 2 blockage
Uses: malignant HTN, Pheochromocytoma, HTN 2° to Clonidine Withdrawal, Cheese Reaction

6. Phentolamine Non-selective Competitive Alpha Blocker
Used in HTN, Cocaine induced HTN.
Decreases the workload of the heart, and decreases the risk of MI

7. Competitve Antagonist Vs. Non-competitive Antagonist

8. Alpha selective Blockers
1 selective: (ends with –sin or –cin)
Prazosin,
Terazosin
Doxazocin,
Tamsulocin
2 selective: (inhibits Negative feedback)
Yohimbine

9. Alpha 1 blockers
Effects: Blocks vaso- and aterioconstriction  vasodilation and arteriodilaton  Decrease in Blood pressure.
Blocks alpha receptors in the eye (pupillary dilator muscle)  Miosis
Reduces Bladder tone and allows for more motility (especially in patients with Urinary retention, BPH)

10. Alpha 1 blockers Uses/Side effects
Drugs  Arteriodilation, used in Raynauld’s Phenomenon
 Increase Urinary Motility, used in Urinary rentention or BPH (Prazosin/Tamsulosin is most commonly used in BPH)
Side effects: Nasal Congestion, Hypotension

11. 2 selective blockers
Yohimbine
Prevents Negative feedback  Increased Release of Epinephrine and Norepinephrine
Claimed to be an Aphrodisiac
Potential uses: Impotence, Co-administrated with drug induced sexual dysfuction

12. phenoxybenzamine
Non-competitive Alpha receptor antagonist - used in pheochromocytoma, malignant hypertension, Clonidine Withdrawal, Cheese Syndrome
Prazosin, tamsulosin, doxazosin
1 selective: uses-mild to moderate HTN, BPH, Raynaud’s
yohimbine
2 antagonist: Used in impotence

13. Beta receptors on body Organs
Eyes: Beta receptors are found in the cillary epithelium in the eye. When stimulated  Produces Aqueous Humor. When blocked, decreases Aqueous Humor production
CVS: Beta 1 receptors are found in the heart. When stimulated  Increase in Heart rate
Pulm: Beta 2 receptors  Bronchodilation

14. Beta blockers (1 selective)
Also known as Cardioselective Beta Blockers, decreases HR
Atenolol
Betaxolol
Esmolol (short half life)
Acebutalol
Metoprolol
ABEAM

15. Beta Non-selective Non Selective Beta blockers Propranolol Timolol
Pindolol
Blocks beta 1 and beta 2 recepors  Bronchospasms and Decrease in HR
Contraindicated in Asthmatics
Decreases aqueous humor production  used in Open Angle glaucoma (Timolol)

16. Uses of Beta Blockers Hypertension - mild to moderate HTN
Angina pectoris -decreases cardiac work load
Cardiac arrhythmias
Myocardial infarction- prevents the reinfarction, prevents the development of ventricular fibrillation

17. Uses of Beta Blockers Glaucoma. Timolol is used
Migraine. Used for prophylaxis
Thyrotoxicosis
Essential tremors
Congestive cardiac failure (carvedilol and labetolol)

18. Side effects of Beta blockers
Beta 2  Exacerbation of Asthma
Masks the sign of a hypoglycemic episode
Bradycardia

19. Alpha and Beta Antagonists
Labetalol (doesn’t cross Placenta, also used in pregnancy)
Carvidilol
Blocks alpha receptors  Decrease BP
Blocks beta receptors  Decreases HR
Used in Severe HTN, Angina

20. Questions What drugs can be given in HTN in pregnancy?
Which is given orally (For home dosing)?
Which is given IV (for immediate tx)?

21. Indirect Adrenergic Antagonist
Resperpine
MOA: Prevents Storage of NE, allowing more MAO to metabolism NE/dopamine. Uses: HTN
Crosses BBB
Side effects: Depression, Suicidal Ideations

23. Pretest Questions
The nonselective β-adrenergic blocking agent that is also a competitive antagonist at α1-adrenoceptors is
a. Timolol
b. Nadolol
c. Pindolol
d. Acebutolol
e. Labetalol

24. Pretest Questions Epineprhine =X
When combined with an antagonist (IC or INC), a shift in the dose response curve occurs. The curve labeled X + INC would most likely occur when vascular smooth muscle is treated with NE in the presence of:
a. Terazosin
b. Phentolamine
c. Labetalol
d. Phenoxybenzamine
e. Prazosin

25. Pretest Questions
A predictably dangerous side effect of nadolol that constitutes a contraindication to its clinical use in susceptible patients is the induction of
a. Hypertension
b. Cardiac arrhythmia
c. Asthmatic attacks
d. Respiratory depression
e. Hypersensitivity

26. Pretest Questions
All of the following drugs are used topically in the treatment of chronic wide-angle glaucoma. Which of these agents reduces intraocular pressure by decreasing the formation of the aqueous humor?
a. Timolol
b. Echothiophate
c. Pilocarpine
d. Isofluorphate
e. Physostigmine

27. Pretest Questions Both phentolamine and prazosin
a. Are competitive antagonists at α1-adrenergic receptors
b. Have potent direct vasodilator actions on vascular smooth muscle
c. Enhance gastric acid secretion through a histamine-like effect
d. Cause hypotension and bradycardia
e. Are used chronically for the treatment of primary hypotension

28. Pretest Questions
A 58-year-old male with angina is treated with atenolol. Select the mechanism of action of atenolol.
a. α-adrenergic agonist
b. α-adrenergic antagonist
c. β-adrenergic agonist
d. β-adrenergic antagonist
e. Mixed α and β agonist
f. Mixed α and β antagonist

29. Pretest Questions
A 75-year-old female with CHF is treated with carvedilol. Select the mechanism of action of carvedilol.
a. α-adrenergic agonist
b. α-adrenergic antagonist
c. β-adrenergic agonist
d. β-adrenergic antagonist
e. Mixed α and β agonist
f. Mixed α and β antagonist

30. Pretest Questions
A 35-year-old male with a pheochromocytoma is treated with labetalol. Select the mechanism of action of labetalol.
a. α-adrenergic agonist
b. α-adrenergic antagonist
c. β-adrenergic agonist
d. β-adrenergic antagonist
e. Mixed α and β agonist
f. Mixed α and β antagonist

31. Pretest Questions
A 65-year-old male has a blood pressure of 170/105 mmHg. Which of the following would be effective in lowering this patient’s blood pressure?
a. Methylphenidate
b. Terbutaline
c. Dobutamine
d. Pancuronium
e. Prazosin
f. Scopalamine

32. Pretest Questions
Which of the following agents might mask the hypoglycemia in treated diabetics?
a. An α-adrenergic agonist
b. An α-adrenergic antagonist
c. A β-adrenergic agonist
d. A β-adrenergic antagonist
e. A cholinergic agonist
f. A cholinergic antagonist

33. Pretest Questions
Which of the following occurs in the treatment of glaucoma with a β-adrenergic antagonist?
a. Decreased aqueous humor secretion
b. Pupillary dilator muscle fiber contraction
c. Dilation of the uveoscleral veins
d. Direct opening of the trabecular meshwork
e. Circular pupillary constrictor muscle contraction

35. Pretest Questions
A 66-year-old male with a one-year history of essential hypertension has minimal response to diet and a diuretic. His blood pressure is now 160/105 mmHg. The diuretic is discontinued, and propranolol is given.
a. α-adrenergic antagonist
b. β-adrenergic antagonist
c. Calcium (Ca) channel antagonist
d. Carbonic anhydrase inhibitor
e. Histamine (H1) receptor antagonist
f. H2 receptor antagonist
g. MAOI

36. Pretest Questions Which drug is used in pheochromocytoma?
a. Pilocarpine
b. Methylphenidate
c. Propranolol
d. Ritodrine
e. Phenoxybenzamine